1. Technical Field
The present invention generally relates to ultrasound systems, and more particularly to an ultrasound system and a method of providing ultrasound images in a duplex mode.
2. Background Art
An ultrasound system has become an important and popular diagnostic tool due to its non-invasive and non-destructive nature. Modern high-performance ultrasound imaging diagnostic devices and techniques are commonly used to produce two- or three-dimensional images of internal features of patients.
Nowadays, the ultrasound system operates in a duplex mode for simultaneously providing ultrasound images in two or more diagnostic modes. For example, the ultrasound system may provide a BD-mode image with a blood flow or movement of a target object indicated. The BD-mode is a diagnostic mode for providing a brightness (B)-mode image and a Doppler (D)-mode image at the same time. The D-mode image may include a spectral Doppler image formed based on Doppler signals, which are obtained from a sample volume set on the B-mode image. The D-mode image may indicate information regarding the moving direction and velocity of a blood flow or moving object. In the spectral Doppler image, a horizontal axis may represent time while a vertical axis represents velocity (or frequency).
In order to obtain the BD-mode image, the ultrasound system may alternately transmit a first ultrasound beam for obtaining the B-mode image and a second ultrasound beam for obtaining the D-mode image. The second ultrasound beam may not be transmitted while the first ultrasound beam is transmitted in the BD-mode. As such, a pulse repetition frequency (PRF) for the second ultrasound pulse may increase. As a result, a velocity scale in the spectral Doppler image may be lowered so that a detectable maximum velocity of a blood flow may be decreased. In order to solve the above problem, the first ultrasound beam may be transmitted for a first predetermined time duration. Then, the second ultrasound pulse may be transmitted for a second predetermined time duration. In such a case, however, the second ultrasound beam may not be transmitted for the first predetermined time duration for transmitting the first ultrasound beam. Thus, a gap corresponding to the first predetermined time duration may occur in the D-mode image.